Scene.Node for ui ?? Ui.Nodebrowsing

@omz, is there any reason not to include a ui.Node? I can see it's not going to be 100% mapping, but can be pretty close. Eg, anything that is about 3D could be a no_op(unless you work in 3D to ui 🆒😁). But the lib seems to contain basically what i am trying to write, but I am sure 100 million times better than I will ever do